Dry air separator



Dec. 22, 1931. H, H. MCKENNA 1,837,915

n DRY AIR SEPARATOR F'iled Nov. 29,` 1927 3 Sheets-Sheet l Dec. 22, 1931. H. H. MCKENNA Y 1,837,915

DRY AIR SEPARATOR Filed Nov. 29, 1927 3 Sheets-Sheet 2 Zfy Zo fr/ t: n1; 9

1U d l (5y/@Wim Dec. 22, 1931. H, H, MCKENNA 1,837,915

DRY AIR SEPARATOR Filed Nov, 29, 1927 3 Sheets-Sheet 3 Patented Dec. 22, 1931A narran STATES PATENT OFFICE HUGH E. MCKENNA, OF IJOS ANGELES, CALIFORNIA, ASSIGNOR, BY MESNE ASSIGNMENTS,

TO WONDERFUL DEVELOPMENT COMPANY,` A CORPORATION OIE NEVADA Y DRY AIR SEPARATOR Application led November 29, 1927.

This invention relates to the classifying of mineral particles and consists of a method and apparatus by which classification o-f the mineral particles is accomplished mainly by controlled air currents. j Y

t is an object of this invention to provide a classifier which isadapted for classifying minerals where the specific weight of the minerals is near that of its gangue. I

Another object of the invention is to provide an apparatus in which two or more minerals having substantially the samespecific gravity may` be separated from its gangue, being collected in separate receptacles.

A further object of the invention is to provide an apparatus in which the mineral is first cleaned andthen separated byV the action of air currents. p

A further object ofthe invention is to provide an apparatus" which lhas a collection chamber which may be set to collect the mineral of any Yspecific gravity desired.

The invention includesa main separator which has a screen through which the mineral particles are drawn by air currents. Sometimes during the operation of theseparator this screen will clog, and when a clogging occurs the efficiency will be greatly reduced.

It is one of the objects of this invention to provide an apparatus in which the: screen when it becomes clogged will be :automatically cleaned.

Tt is one of the objects of theinvention to provide a method of separating mineral particles from its gangue, in which methodL the separation is accomplished by controlledair currents. V 1 f l Other objects and advantages will appear in the following description. l The invention may be best y.understood by reference to thev accompanying diagrammatic drawings in which: j

Fig. 1Ais an elevational view, partly sectioned, of the apparatus of my invention.

F ig. 2 isa section taken on the line 2.-,-2 of F ig. 1. l

Fig. 3 Vis a section'f'taken on the line 3k-3-of Fig. 1. v l

Serial No. 236,439.

Fig. 4 is a section taken on the line 4 4 of Fig. 1. Y Y

Fig. 5 is a section taken on the line 5-5 of Fig. 1.

Referring to the drawings-in detail7 the numeral 11 represents ashell, the upper end of which isconical, as indicated at 12, and is provided with an air inlet conduit 13. The lower end of the shell 11 is conical at 15 and has a gangue discharge 16. The ground material which consists of the mineral and its gangue'is introduced into the upper part of the shell 11 by means of an inlet 18.

Supported in the upper part of the shell 11 isa breaking device 19 which checks the fall of the comminutedinaterial, scatters any lumps which may be present, and distributes the material evenly through the casing. This breaking device 19 consists of an upper con.- ical screen 20 and a lower conical screen 21, these screens being placed with their bases together. The upper screen 20 is preferably about 70 mesh and the lower screen is prefer-' ably about 90 mesh. The lower part of the lower conical screen 21 is provided with an opening 23 through which a nozzle 24 is extended. The upper part of the nozzle 24 Ais situated in a space 25 in the breaking device 19 and has branch pipes'26 connected thereto. These branch pipes extend radially outward at an angle of ninety degrees from each other to the exterior of the shell 11 where they are joined to a manifold 28; The manifold 28 Y has an inlet 29, the size of which is controlled by adamper 30. i A

Situated in the she-1111 below the breaking device .19 isa classifying device 32. t This classifying device. 32 includes an upper conical screen 33 which is preferably from 8O to j 100 mesh. The apex of this conical screen 33 may extend into the lower endof the nozzle 24 if desired; f The lower partof the classifying device 32 is in the form of a conical mem-j ber 34 which is provided with screened openingsy 35. The interior .36 of the classifyingl device 32 is connected to a suction conduit 38 which extends to the exterior of the shell 11, as shown. Y Surrounding the conical member 34 is a frusto-conical baiie 39 which provides an annular confined space around the coni` cal member 34. Connected to this annular confined space 40 is a conduit 41 which extends to the exterior of the shell 11. The conduit 41, as shown, is connected to the conduit 38, and the conduit 38 is provided with a suction blower 42 which places a suction on the interior of the shell 11. V v

When the blower is in operation, air is drawn into the shell 11 through the conduit 13 and through v'the nozzle 24. Air-is also drawn in through openings 44 and 45 in the shell 11 which are controlled by dempers 46 and 47 respectively. The openings 44 'and 45 are so regulated and the air is drawn .into the shell 11 in such a manner that there is a violent a'gitationin an agitation chamber 48 provided by the shell 11 between the breaking-device 1-9 and theclassifyi-ngdevice 32.

The conduit 38 is provided with an `automatic relief valve 50 which is placed at the end of a pipe 51. This relief valve is pivoted at 52 and is'provided with a weight 53 which normally holds it infclosed position. Vhen theclassifying device 32 becomes clogged, the suction in the conduit 38 is increasedand the relief valve is swung'into the position indicatedby dotted lines 54.V This permits a sudden inrush of air which `ows upward through the interior 36, blowing any material from'the screen 33. AThe conduitl 41 is provided witha trap Y56 in which mineral particles may be collected. This trap 56 has aY baiiie 57 in the interior around which the flow of air carrying the particles must pass. The upper part of the trap is provided with openings 58 which `are controlled by a damper 59. The collected material may be removed from the trap through a lower valve control lspout 60.

The conduit. 38, between the point where the conduit 41 attaches to it and the point Where the sucti'on'blower 42 is located, is provided with a pluralityL of traps 62 and 63. Each of thesetraps is connected to thecon duit 38'by a short tube 64. The traps'fpro vide closed collection chambers into which Y lected material may be withdrawn through a lower valve controlnspout.69.v The ltube 64 is provided with suitable Vloafles 7 0 which prevent agitation in the chamber 65 *ofl each The operation of the invention, ust: described, is substantially as follows:

The blower .is set into operation so as to provide air currents inside the Vshell 11 which Will be described in connection with the passage of the material throughthe apparatus. The material from which `theyminer'al is to be obtained is introduced throughpthe inlet 18. This material is cr'ushedso thatit is below 200 mesh.Y Thelmaterial falls vdownward '-1 onto the breaking device 19. Almost all of the material will pass through the upper screen 20, the space 25, and the lower screen 21. Any particles which are larger than 20() mesh are carried through the annular passage between the shell and the upper screen 20, as indicated by arrows 72. These particles are usually heavy enough so that when they reach a point at the largest diameter of the breaking device 19 they fall straight downward through the agitationchamber 48 an-d outwardthrough the gangue discharge 16. The material passing through the break- 'ing device 19 is screened and divided so that none of it is lumped together. This screened material drops into the agitation chamber 48 where vviolent agitation is taking place, as indica-'ted byarrows 7,1, due to the conliuence of the currents Eof'air entering the agitation chamber lfrom the nozzle 24 and the openings 44 and 45. This violentY agitation has the efect of thoroughly 'cleaning the mineralv drawn through the screen 33 by the suction e placed on theinterior 36 bythe blower 42. It is vthe heavier particles of mineral which pass through the g--screen' 33. At this` time alstream .of air is being drawn inward .through the nozzle 24. This stream of air passesdownward, as indicated by arrows 73, along the surface ot the screen 33 and tends to wash Athe light particles of gangue Yand the small particles of mineral from the screen 33. These particles pass downward around the largest diameter of the classifying-device 32 and meet in an upiow ofiair which is bei-ng drawn inward through the gangue discharge 16 due to the action of the blower Y42. This has the effect of causing the light particles of gangue and small particlesof mineral to pass into vthe confined space 40 provided by therchamber 39. Any heavy particles of gangue which may be present are too heavy to be affected by the upfiow of air through the gangue discharge 16 and will therefore pass downward and outward, as indicated by the arrows 7 4'. The suction in the interior'36 of theclassifying device 32 draws most of the mineral particles of the material inthe closed yChamber 40 Yinto the interior of 36 of the classifying device 32. This mineral passes outward through the conduit 38. The material which is not drawn 'through the screens 35 is drawn through the conduit 41.

The current `of air flowingthrough the conduit 38 carries the gangue particles therealong until the first trap 62 is reached. The operation' of the `1traps is substantially the same and comprises an important part of the invention. Y When the damper:` 67 is closed, all of the mineral particles may drop into` the collection chamber.. This depositionk is facilitated by the upwardbend in the conduit above the opening of thetrap, since the inertia of the particles tends to carry them in a straight line and therefore out of the main current of the air stream. Since the air cur` rent is created due to the lowering of the pressure in the conduit by the blower 4t2 the pressure in the conduit above the trap is less than atmospheric pressure. Itiwill be seen, therefore, that when the damper 67 is operated to admit airV through the openings 66 this air will pass upwardly into the conduitthrough the material falling into the collection chamber, and prevent the deposition of the lighter particles. Accordingly, if the openings k66 are closed,a lc rge range of mineral particles will be collected, and if the openings 66 are open, a narrow range of mineral particles will be collected; that is, only the heaviest particles will be collected. As the material passes over the first trap 62, the heaviest part of the mineral particles may be removed, and as the material passes over the second trap 63, the lightest part of the mineral particles may be removed. Any silt or small gangue particles will pass with the current of air through the blower 42.

rlhe trap 56 operates in substantially the same manner as the traps 62 and 63, and the. mineral particles deposit according to the amount of air introduced into the trap 56 through the openings 58. As the material clogs in the classifying device 32, the vacuum in the conduit 38 and in the interior 36 increases to the eXtent that the relief valve 58 is moved into the position shown by dotted lines 54. This allows an increase of air which reduces the vacuum. This flow of air will pass upward into the interior 36l and tend to flow outward through the screen 33. This forces the clogging particles from the screen. The relief valve 5() will immediately return to proper closing position and normal operation of the apparatus will continue.

The present invention is useful for separating metallic or non-metallic minerals from their gangue. The apparatus shown may be regulated to suit any material by controlling the air currents in the shell ll and by controlling the vacuum in the traps 56, 62 and 63. If desired, the air which is drawn into the shell ll through the conduit 13 and the nozzle 24 may be heated air so that no moisture may be absorbed by the comminuted material, which would tend to interfere with the cleaning action in the agitation chamber 48 and in the classification of the mineral.

The lower screens 35 of the classifying device 32 are used only when the vmaterial to be classified is of a light specific gravity. l/Vhen the mineral is of a heavy specific grav-l same.

ity it is found that these screens 35 are not necessary.

As previously eXplained,'this invention is useful for separating two or more products from the same gangue. If the products are of different specific gravities, the traps 56, 62 and 63 may be adjusted so that the particles may be separated according to their weights. It often occurs that a gangue will carry two minerals which are of substantially the same specific gravity. In my invention the minerals of the same specific gravity may be collected in the different traps even though their weights are substantially the The reason for this is that the fracture of different minerals differs so that some minerals provide larger exposed surfaces. The air currents act differently upon the minerals according to the exposed. surfaces. Although I cannot exactly explain just how this action takes place, I have demonstrated by using a device of the character of my invention that gangue carrying two minerals of substantially the same specific weight may be passed through the apparatus and one mineral may be deposited in one trap and the other mineral deposited in the other trap.

llfrom the foregoing description it will be seen that the invention provides a classifier which for its operation relies upon the combination of suitable baffles and deflectors which operate to direct and control air currents. The air currents are controlled and directed so as to first distribute the fine material kintroduced into the top of the shell ll so that when the material has passed through the breaking device 19 there will be no lumps present. The air currents then thoroughly clean the mineral and separate it from the gangue. The air currents then carry the mineral and any silt` particles through the conduit 38 where the minerals may be deposited in the traps 62 according to their weights by controlling the admissionl of air through the openings 66 or 58 into thetraps.

As far as I am informed, the invention is new in its entirety and the different apparatus of thecomplete combination are also new.

- I claim as my invention:

l. Apparatus for classifying comminuted material comprising a primary chamber having inlet openings for the admission of comminuted material and air, a secondary chamber, a passage connecting said chambers, means for reducing the air pressure in'said secondary chamber whereby a current of air will pass into said primary chamber and through said secondary chamber, said primary chamber embodying a chute through which a stream of said comminuted material T125 is adapted to pass by the action of gravity, an opening adjacent said chute communicating with the said passage whereby a current of air will be drawn through said stream of material in said chute and the portion of said 13C' material `having the lower specific gravity will be carried into'said secondary chamber, said Secondary chamber embodying anupper portionv so constructed as to cause the ysaid material carried by said current of air to be deposited, and a lower portion to receive the deposited material, said lower portion having adjustable openings vfor the admission of air, whereby an upwardly moving current ofair may be created to prevent the deposition of the portion of said material having they lower specific gravity.

2. In a separator, a classifying chamber covered 'by an inclined screen, means for creating a suction within said classifying chamber, means vfor directing a current of air anda stream ofcomminuted material against the upper portion of said screen, and means for :directing a current of air against said screen at an anglek to said first current of air insuch a manner as to retard the flow of said material and agitate the same.

3. a separator, a classifying chamber covered by an inclined screen, means for creating a suction within said classifying chamber, means for directing a stream of air and comminuted material against the upper portion of said screen, and means for direct-v ing a second stream of air against said screen,

said last mentioned means being located below the top of said screen, whereby eddy-currents are created at the confluence of said streams to retardand agitate said material.

4. In a separator, a classifying chamber having an inclined upper wall serving as a deflector and an oppositely inclined wall, an outer wall'substantially parallel to said lower wall forming a channel therebetween, a baille substantially parallel to said two walls connected at its lower end to the said lower wall of Y said classifying chamber and dividing said channel into inner and outer passages, means for creating a suction within said inner passage, means for directing a current of air and a stream of comminuted material against said deilector whereby said air and material will flow along said delector into said channel, and means for admitting a current of air into the lower endof said outer passage, said aircurrents bein@` so adjusted that the lighter portion of said material will be drawn into said inner passage and the heavier portion of said material 4will pass into said outer passage.

5. A classifying device comprising a casing, inlet means in said casing for the admission of comminuted material, air inlet means in said casing, a classifying chamber within said casing, a screen covering said chamber, means for reducing the ai-r pressurein said chamber, whereby during normal operation a current of air and a 'stream of said material are drawn into said casing and through said screen, said air inlet being so adjusted that the pressure in said casingis normally below atmospheric pressure, a pipe leading from said chamber and opening outside said casing, a valve in saidpipe adapted to remain closed during normal operation,and to `open when the pressure insaid chamber is lowered, whereby any clogging of said screen by said comminuted material will cause said valve to open, and the inrush of air through said pipe will clean said screen.

6. A trap forcollecting comminuted material carried in suspension in a current of air below atmospheric pressure, comprising a conduit through which said current of air is adapted to passan opening in the lower side of said conduit communicating with a collection chamber located below said conduit whereby said vmaterial is adapted to pass by gravity into said chamber, air yinlet means in said chamber for allowing air to How into said chamber and upwardly through said material into said conduit, said air inlet means being adjustable to control the range of specific gravity of the material deposited in said chamber.

7. A trapA for collecting comminuted material carried in suspension in a current of air below atmospheric pressure, comprising a conduit throughwhich said current of air is adapted to pass, an openingin the lower side of said vconduit communicating with a collection chamber located below said conduit whereby said material is adapted to pass by gravity into said'chamber, air inlet means in said chamber for allowing air to flow into said chamber and upwardly through said material into said conduit, said air inlet means being adjustable to' control the range of specific gravity of the material deposited in said chamber, and baffles between said pipe and said chamber to prevent the production of eddy currents in said chamber.

8. A trap for collecting comminuted materiarl carried in suspension in a current of air below atmospheric pressure, comprising a conduit .having a horizontal portion and a vertical portion, through which said current of air is adapted to pass, an opening inthe lower side of said conduit at the junction of said horizontal and vertical portions communicating with a collection chamber located below said conduit, whereby said material is adapted, under the influence of gravity and inertia, to pass into said chamber, air inlet means in said chamber `for allowing air to flow into said chamber and upwardly through said material into said conduit, said air inlet means being adjustable to control the range of specific gravity of the material deposited in said chamber.

9. In a classifying apparatus ofthe character described, the combination of: a shell; a breaking device; inlet means for passing a comminuted materia-l onto said breaking device; a classifying device in said shell be low said breaking device; means for placing a suction on said classifying device, said suction drawing air into said shell, said air carrying the mineral particles of said comminuted material through said classifying device; and an air inlet nozzle arranged to admit a current of air against the surface of said classifying device between said surface and said comminuted material.

10. In a classifying apparatus of the character described, the combination of: a shell; a breaking device; inlet means for passing a comminuted material onto said breaking device; a classifying device in said shell below said breaking device; means for placing a suction on said classifying device, said suction drawing air into said shell, said air carrying the mineral particles of said comminuted material through said classifying device, said air being admitted into said shell in such a manner that violent agitation takes place in said shell between said breaking device and said classifying device; and an air inlet nozzle arranged to admit a current of air against the surface of said classifying device between said surface and said comminuted material.

11. In a classifying apparatus of the character described, the combination of: a shell; a breaking device; inlet means for passing a comminuted material onto said breaking device; a classifying device in said shell below said breaking device; means for placing a suction on said classifying device, said suction drawing air into said shell, said air carrying the mineral particles of said comminuted material through said classifying device; a baflle forming a confined chamber adjacent said classifying device into which a part of said mineral not passed through said classifying device will pass; and a pipe connected to said confined chamber through which the mineral in said confined chamber is drawn, said pipe being connected to said means for placing a suction on saidfclassifying device.

12. In a classifying apparatus of the character described, the combination of: a shell; a breaking device; inlet means for passing a comminuted material onto said breaking device; a classifying device in said shell below said breaking device; means for placing a suction on said classifying device, said suction drawing air into said shell, said air carrying the mineral particles of said comminuted material through said classifying device; a baffle forming a confined chamber adjacent said classifying device in which a part of said mineral not passed through said classifying device will pass; a pipe connected to said confined chamber through which the mineral in said confined chamber is drawn; and a trap connected to said pipe.

13. In a classifying apparatus of the character described, the combination of: a she-ll; a breaking device; inlet means for passing a comminuted material onto said breaking device; a classifying device in said shell below said breaking device; means for placing a suction on said classifying device, said suction drawing air into said shell, said air carrying the' mineral particles of said comminuted material through said classifying device; a baffle forming a confined chamber adjacent said classifying device into which a part of said mineral not passed through said classifying device will pass; a pipe connected to said confined chamber through which the mineral in said confined chamber is drawn, said pipe being connected to said means for placing a suction on said classifying device; and a trap connected to said pipe.

14:. In a classifying apparatus, a casing, means for admitting comminuted material into said casing, a screen within said casing, for separating the coarse and fine particles of said material, means for conveying the fine particles from said casing and classifying` the same according to specific gravity, and separate means for conveying the coarse particles from said casing and classifying the same according to specific gravity.

15. In a classifying apparatus, means for creating a continuous current of air, means for suspending comminuted material in said current of air, a screen for separating the coarse and line particles of said material, a portion of said current of air passing through said screen and carrying the fine particles, and a portion of said air passing around said screen and carrying the coarse particles, and independent means for classifying said coarse and fine particles according to specific gravity.

In testimony whereof, I have hereunto set `my hand at LosAngeles, California, this 23rd day of November, 1927.

HUGH H. MGKENNA. 

